Identification of mineral particles in pneumoconiotic lungs

Our plain-English summary of Identification of mineral particles in pneumoconiotic lungs, by W.J. Henderson, J. Gough, J. Harse (Journal of Clinical Pathology, 1970).

The study

• Authors: W.J. Henderson, J. Gough, J. Harse
• Journal: Journal of Clinical Pathology
• Published: 1970;23(2):104-9
• Cited by: 6 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

An extraction replication technique has been used for the study, by electron microscopy, of lung tissue from a number of different cases of pneumoconiosis. The technique provides a relatively simple means of studying the surface area of replicated tissues, and any foreign particles present which are either replicated or extracted from the tissue can be identified. A set of standard micrographs of different types of mineral particles likely to be encountered should be kept for reference. Most of the particles identified by this technique were beyond the limits of resolution of optical microscopy. Furthermore, the procedure involves the minimum of chemical and physical treatment. The histochemical diagnosis and industrial history was confirmed in the first two cases described, by the electron microscopy investigations. The third case presented an uncertain histological and industrial history, but an electron microscopy study confirmed the presence of the mineral particle considered responsible for the clinical condition. The fourth and fifth cases described illustrate the use of this technique in identifying a particular type of pleomorphic mineral, and illustrating its position in situ in relation to surrounding tissue.

In plain English

This 1970 article described an electron microscopy method, called extraction replication, for identifying mineral particles in lung tissue. The authors applied it to unstained paraffin tissue sections, prepared for routine examination, from five patients with pneumoconiosis. In a patient who had bagged kaolin in the china clay industry for more than 30 years, the method showed kaolinite particles. In a patient exposed to Norwegian talc for 20 years, it identified talc particles. In a third patient, neither the work history nor the tissue examination explained the lung scarring. There the method found large quantities of mica crystals and no other particles, and the authors assumed mica was a factor in the disease. Two patients had asbestosis. In one, who had worked in the crushing room of an asbestos factory, the fibres were chrysotile and no other asbestos type was found. In the other, a former mattress maker and shipyard pipe lagger, the fibres were of the amosite or crocidolite group, with a 90-degree fracture angle suggesting amosite. The authors concluded the technique was of particular value because many particles were too small for optical microscopy.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Description of a laboratory method (extraction-replication electron microscopy) illustrated with a series of five case descriptions
• Who was studied: Lung tissue from five patients with pneumoconiosis, prepared as unstained paraffin sections for routine histology. Two of the five had asbestosis. The article does not give where or when the patients were seen.
• Exposure: The five patients' exposures were:
• Kaolin: bagging in the china clay industry for more than 30 years.
• Norwegian talc: 20 years.
• Unknown dust in a former soldier, later found to be mica of unknown source.
• Asbestos: work in the crushing room of an asbestos factory from 1931.
• Asbestos: 30 years with various types of asbestos as a mattress maker and then lagging pipes in a shipyard.
• Main results:
  • Case 1 (kaolin bagger, aged 67 at death): electron microscopy of tissue replicas showed typical kaolinite particles, confirming the histological diagnosis of kaolinosis.
  • Case 2 (Norwegian talc exposure, aged 54): electron microscopy identified talc particles in the lung tissue. The authors noted that the same surface pattern can be seen on anthophyllite, which is often mistaken for talc.
  • Case 3 (diagnosed with silicosis, died aged 40; fibrosis from dust of unknown constitution): large quantities of mica crystals were found and no other particles. The authors assumed mica was a factor in causing the pneumoconiosis.
  • Case 4 (asbestosis, aged 46 at death, asbestos factory crushing room): a mass of fibres in the lung was identified as chrysotile, and no other type of asbestos was found.
  • Case 5 (asbestosis, aged 57 at death, mattress maker and shipyard pipe lagger): the asbestos fibres were of the amosite or crocidolite group. A 90-degree fracture angle suggested amosite, and some fibres were surrounded by ferritin beads.
  • In the asbestosis cases, the optical micrograph showed asbestos bodies but did not allow the type of asbestos causing the fibrosis to be identified.
• The authors' conclusion: The authors concluded that the replication technique is of particular value for identifying mineral particles too small for optical microscopy. They added that it can be applied retrospectively to unstained paraffin sections stored in pathology department records.
• Limitations the authors state:
  • The authors noted that telling amosite apart from crocidolite has always been a particular problem. They suggested electron or laser diffraction might help.
  • In case 3, the patient's history did not reveal the source of the mica.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Talc and vermiculite.

Medical terms in this study, explained in our Lexicon: Pneumoconiosis, Pleomorphic.

Related studies

• A striking deposition of mineral particles in the lungs of a farmer: a case report — B. Gylseth, L. Stettler, et al. (1984)
• Quantitative x ray microanalysis of pulmonary mineral particles in a patient with pneumoconiosis and two primary lung tumours — S. Anttila, S. Sutinen, et al. (1984)
• Pulmonary mineral dust. A study of ninety patients by electron microscopy, electron microanalysis, and electron microdiffraction — J.P. Berry, P. Henoc, et al. (1976)
• Angular and fibrous particles in lung in relation to silica-induced diseases — A. Dufresne, R. Bégin, et al. (1998)
• Accumulation of mixed mineral dusts in the lungs of rats during chronic inhalation exposure — C.H. McMillan, A.D. Jones, et al. (1989)
• The second diagnosis: the role of the pathologist in identifying pneumoconioses in lungs excised for tumor — E.J. Mark (1981)

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